Gray System Theory In The Study Of Tunnel Engineering

Tunnel project is the construction of the underground tunnel-style buildings, due to its occurrence particularity and complexity of the environment, the tunnel construction is a difficult technical problems. Accurately determining the stability of surrounding rock and effectively controlling and mastering the surrounding rock deformation is a key component of the tunnel construction and supporting. Tunnel project is a complicated gray systematic project, affected by many factors,in particular, the objective existence hydro-geological factors, which have a greater impact on the project because of its many uncertain factors, and it is not common to fully grasp the geological situation before and in its construction. So we must seek a new theory or method with a small amount of information and data to predict and explore more things in the underlying trend or pattern. In the tunnel construction, we not only have to ensure the construction safety, but also to make a scientific and rational decision-making to achieve the goals of tunnel engineering safety and economy.In this paper, based on systematically understanding and studying the gray system theory, combining with the characteristics of the tunnel projects and making engineering theories and practices together, several key aspects be do depth study and calculate in the tunnel projects, propose a new gray evaluation method and prediction models, have great practical value and guide effect in project construction. The main contents of this paper is as follows:1.Based on summing up the various rock classification methods, develop a number of single indicators and integrated analysis approaches, determine the correlation by use of gray system correlation theory, and accurately determine the rock classification according to the measured indicators.2.On the basis of comparison and analysis of the construction programs, determine the most reasonable comprehensive evaluation index for the construction of the tunnel, then in accordance with the various impact indicators of specific projects, using gray system plan-decision theory, to make the analysis and calculation, and identify the best construction programs. 3.According to the use of the three kinds of predictive models, the GM (1,1),DGM (2,1) and Verhulst,of gray system theory in the Yi Hong Ji Shi engineering, identify the GM (1,1) model as a forecasting model for this project after a comparative analysis to carry out rock deformation prediction which has high accuracy and meeting the engineering requirements of the deformation.4.By studying the gray model of Verhulst, according to its characteristics, we can predict the ultimate and maximum displacement value of surrounding rock deformation by using this model.5.According to the characteristics of surrounding rock deformation, combining the models GM (1,1) with Verhulst to determine the destruction time of displacement of surrounding rock.